2,361 research outputs found
Conductance oscillations in mesoscopic rings: microscopic versus macroscopic picture
The phase of Aharonov-Bohm oscillations in mesoscopic metal rings in the
presence of a magnetic field can be modulated by application of a DC-bias
current I_DC. We address the question of how a variation of I_DC and hence of
the microscopic phases of the electronic wave functions results in the
macroscopic phase of the conductance oscillations. Whereas the first one can be
varied continuously the latter has to be quantized for a ring in two-wire
configuration by virtue of the Onsager symmetry relations. We observe a
correlation between a phase flip by +/- pi and the amplitude of the
oscillations.Comment: 4 pages, 4 figure
Long-wavelength absorbing forms of bacteriochlorophylls. II. Structural requirements for formation in Triton X-100 micelles and in aqueous methanol and acetone
PHYCOBILISOMES AND ISOLATED PHYCOBILIPROTEINS. EFFECT OF GLUTARDIALDEHYDE AND BENZOQUINONE ON FLUORESCENCE
The fluorescence of the biliproteins C-phycocyanin from Spirulina platensis, B-phycoerythrin
from Porphyridium cruentum and of isolated whole P. cruentum phycobilisomes is quenched in the
presence of glutardialdehyde (GA) or benzoquinone (BQ). The kinetics of fluorescence decrease thus
induced is biphasic. If GA is used as a quencher, the fluorescence can be recovered at 77 K. Contrary to
the GA-effect, only a minor recovery takes place with BQ at 77K, thus demonstrating a different
mechanism of action of GA and BQ on biliprotein
A case study of perceptions of value for students at a private, liberal arts college in the Midwestern United States
Dissertation supervisor: Dr. Carole Edmonds.Includes vita.Large amounts of quantitative data can be obtained by means of the National Survey for Student Engagement (NSSE). However, can a 15-minute survey truly provide an institution with enough relevant data to adequately understand a student's perception of value in order to help inform strategic changes that will affect future levels of engagement? Harper (2007) suggests that quantitative assessment has overwhelmed significant qualitative research efforts, limiting potential insights gained from a student's valuable first-hand experience. Whereas student success can be measured at the end of a semester, school year, or educational career, qualitative measurement of a student's perception of value reflect how their learning experience evolves over the course of their entire college experience. This qualitative bounded case study examines the perceptions of value for students at a private, liberal arts college in the Midwestern United States.Includes bibliographical references (pages 199-209)
Structures of antenna complexes and reaction centers from bacteriochlorophyll b-containing bacteria
Ultrafast process in bacterial antennas studied by nonlinear polarization spectroscopy (frequence domain)
Substructure analysis of the bacterial antenna LH II by nonlinear polarization spectroscopy in the frequency domain
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